The present invention relates to inks having a color forming reactant which changes color by the application thereto of a coreactant. More particularly, the present invention is directed to latent inks which provide for the formation of uniformly dispersed color forming reactant with a thin, clear film when the ink is applied to a substrate.
Latent inks are known, per se. Examples of heretofore known latent inks and their uses are disclosed in the following issued U.S. patents.
U.S. Pat. No. 3,454,344 issued on July 8, 1969 to J. W. Ryan.
U.S. Pat. No. 3,473,807 issued on Oct. 21, 1969 to R. Leonard.
U.S. Pat. No. 3,600,827 issued on Aug. 24, 1971 to Denys Fesher.
U.S. Pat. No. 3,617,325 issued on Nov. 2, 1971 to Raymond E. Spokes.
U.S. Pat. No. 3,682,673 issued n Aug. 8, 1972 to W. J. Manske.
U.S. Pat. No. 3,826,499 issued on July 30, 1974 to L. G. Lenkoff.
U.S. Pat. No. 3,850,649 issued on Nov. 26, 1974 to D. D. Buerkley.
U.S. Pat. No. 3,920,863 issued on Nov. 18, 1975 to Robert Fraike.
U.S. Pat. No. 4,111,462 issued on Sept. 5, 1978 to Heinz E. Lange.
U.S. Pat. No. 4,139,965 issued on Feb. 20, 1979 to Beverly J. Curry.
U.S. Pat. No. 4,188,431 issued on Feb. 12, 1980 to P. E. Sokol.
U.S. Pat. No. 4,212,393 issued on July 15, 1980 to Leon G. Lenkoff.
All of the latent inks heretofore known to us have the drawback that when they are applied to a fabric substrate they are absorbed into the substrate material which can result in blurred or fuzzy images when the latent ink is developed. Further, when different color heretofore known inks are applied in close mutual proximity on a substrate, they tend to bleed together or into one another resulting in muddied colors when developed.